The OEM crank comes with all the main bearing shells, and the BMWNA MSRP for that is $2,698.37. Ordering from BMW Morristown online parts site gives a price of $1,869.97. So for less than $1900 including the main bearing shells, I'd for of OEM (P/N: 11210443639).

For those that are into horror here are some pics. (sorry Iphone, will get better soon)

Some pretty decent wear on the mains, you can see the crank damage.

Two of the mains and crank are clearly fkd, we also found a slight imperfection on the block, it's like small pitting, you can also see it on the outside of the main shell. I'll get some detailed pics.

Let me get this straight... You are swapping out parts designed by some of the top engineers in the world because some guys sponsored by a company told you it's "better??" But when you ask the same guy about tracking, "oh no, I have a kid now" or "I just detailed my car." or "i just got new tires."

The crank load is a possibility. I do not know the physics of the shorter V8 crank, but on the longer inline 6 cranks in the E36, RMS and Dinan both used extended crank pulleys with an extra drive for a dedicated supercharger belt. No issues ever reported. Most supercharger kit sellers these days use the existing accessory drive and a longer belt. The accessory drive seems to work pretty well -- I am surprised belt slippage has not been an issue, but it has not.

Well the motor this kit came off, and mine both have damaged their 1st and 2nd mains and both are currently being rebuilt. There is also another car in Australia which had a stage one and was rebuilt.

Now I know there are lot of these kits in the states but in Oz I've only heard of about 3 people running these kits, so that's a 100% failure rate.

Yes as you say I've looked into a few of the other kits (ESS for example) and as you say they use the existing pulley. Mine actually did have slippage and the pulley and belt was replaced, so it was even tighter and likely put even more tension on the crank.

Not pointing fingers yet.. just seems like a cluster of failure from what I can see.